In recent years, luminescence efficiency of light emitting diodes (LED) has been constantly improved. Consequently, fluorescent lamps and incandescent bulbs are gradually replaced with LEDs in some fields, such as scanning light source which requires high speed response, back or front light source of a liquid crystal display (LCD), automobile dashboard illumination, traffic signs, and general illumination devices. Typical LEDs are usually semiconductor devices which use III-V compounds, such as GaP, GaAs, and so on. LEDs convert electrical energy into light. When an electric current is applied to a semiconductor device with the aforesaid compounds, energy is released in the form of light through the combination of electron and electron hole. LEDs have advantages, such as faster response (about 10−9 S), smaller size, lower power consumption, less pollution, higher reliability, and capability for mass production. Accordingly, LEDs are widely applied in many fields.
FIG. 1 is a schematic cross-sectional view depicting a conventional light emitting diode package structure. Referring to FIG. 1, a conventional light emitting diode package structure 100 consists of a LED chip 110, a carrier 120, a conductive line 132, a conductive line 134, and a molding compound 140. Herein, the LED chip 110 is disposed on the carrier 120, and the conductive line 132 and the conductive line 134 electrically connect the LED chip 110 with the carrier 120 respectively. The molding compound 140 is disposed on the carrier 120 and covers the conductive line 132 and the conductive line 134. The LED chip 110 is applied voltage difference through the conductive line 132 and the conductive line 134, and thereby a light emitting layer 112 of the LED chip 110 emits light and generates heat.
It is noted that the carrier 120 and the molding compound 140 of the conventional light emitting diode package structure 100 have poor thermal conduction efficiency. Consequently, heat generated by the light emitting layer 112 of the LED chip 110 can not be released effectively. When a high electric current is applied, the LED chip 110 is easily damaged for being overheated. Hence, a conventional method, which uses a thermal conductive material, such as metal, to fabricate the carrier 120, is provided to improve the thermal conduction efficiency of a bottom 114 of the light emitting diode package structure 100. However, such a method does not improve the thermal conduction efficiency of a sidewall 116 of the LED chip 110.